Musannaf Ibn Abi Shayba 13:287

Hushaym narrated to us, from Mughirah, from Ibrahim, that a black friend of his wrote to him to buy a slave girl for him, and he did so. He then found a fault in something of the slave girl’s leg. He said: That reached the black man, regarding his statement, so he said: "I would not have liked that I had looked at her legs, nor at such and such."